Forest UCM PnCP

From New IAC Wiki
Jump to navigation Jump to search

Charged Particle in uniform B-Field

Consider a charged particle moving the x-y plane in the presence of a uniform magnetic field with field lines in the z-dierection.

v=vxˆi+vyˆj
B=Bˆk


Lorentz Force
F=qE+qv×B
Note
the work done by a magnetic field is zero if the particle's kinetic energy (mass and velocity) don't change.
W=ΔK.E.

No work is done on a charged particle force to move in a fixed circular orbit by a magnetic field (cyclotron)


F=ma=qv×B=q(ˆiˆjˆkvxvy000B)
F=q(vyBˆivxBˆj)

Apply Newton's 2nd Law

max=qvyB
may=qvxB
maz=0


Motion in the z-direction has no acceleration and therefor constant (zero) velocity.
Motion in the x-y plane is circular

Let

ω=qBm = fundamental cyclotron frequency

Then we have two coupled equations

˙vx=ωvy
˙vy=ωvx


let

v=vx+ivy = complex variable used to change variables
˙v=˙vx+i˙vy

http://hep.physics.wayne.edu/~harr/courses/5200/f07/lecture10.htm


http://www.physics.sfsu.edu/~lea/courses/grad/motion.PDF

http://physics.ucsd.edu/students/courses/summer2009/session1/physics2b/CH29.pdf

http://cnx.org/contents/77faa148-866e-4e96-8d6e-1858487a520f@9

Forest_Ugrad_ClassicalMechanics